The present invention relates to a method of assembling a grommet and a jig for assembling a grommet used for drawing out a wire harness from a case, for example, a waterproof box containing a control unit or the like at inside thereof.
For example, JP-UM-A-3-126315 discloses a related grommet used in a waterproof box. As shown in FIGS. 8A and 8B, a related grommet 80 is formed with a second thick-walled peripheral wall portion 83 at a middle portion of a bellows-like barrel portion 82 of a grommet main body 81 and formed with a fitting groove 84 and a guide projected streak 85 constituting a fitting portion for fitting to a rigid plate on a periphery of the second thick-walled peripheral wall portion 83.
A lower half 85 of the second thick-walled peripheral wall portion 83 is formed in a semicircular shape and an upper half 86 thereof is formed in a rectangular shape. Further, a first thick-walled peripheral wall portion 87 on a front end side is formed also by a similar shape to be larger by one size and an inner periphery thereof is formed with a fitting groove 88 for fitting to a rigid member. An outer peripheral portion of the first thick-walled peripheral wall portion is formed with an upper end rip 89.
According to the grommet 80, the rigid member is fitted onto the inner periphery of the first thick-walled peripheral wall portion 87 on the front end side of the grommet main body 81, a locking claw thereof is inserted to lock into a locking frame portion of a lower case and a sliding projected streak 90 and a sliding peripheral groove 91 of the first thick-walled peripheral wall portion 87 and a guide groove and a guide projected streak of the lower case are fitted to each other. An upper case having a packing for the upper end lip 89 is made to cover an upper side of the first thick-walled peripheral wall portion 87.
Further, the fitting groove 84 of the second thick-walled peripheral wall portion 83 on the middle side and a guide projected streak and a fitting groove are fitted each other and the locking claw of the lower side rigid plate is inserted to lock to a locking frame portion of a wall plate of a heat shielding plate or the like. An upper wall is fitted to fixed to a fitting plate of the upper side unit plate.
However, in the case of the above related grommet, it is necessary to perform a fitting operation after positioning both of the rigid members constituted by two parts and there is a problem that fitting operability is poor.